Device and method for processing images to determine a signature of a film

Abstract

A method of processing images to determine at least one signature of a film. The method includes a step of selecting chronologically a series of images from said film, a step of evaluating shifts relating to at least one descriptor corresponding to a physical property between consecutive images in order to obtain primary visual shifts, a step of calculating differences between said primary visual shifts to determine secondary visual shifts, a step of calculating differences between said secondary visual shifts to determine tertiary visual shifts, and a step of determining a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts to obtain the signature of the film.

1. A method of processing images to determine at least one signature of a film, comprising the steps of:
 selecting chronologically a series of images from the film; 
 obtaining primary visual shifts as shifts of at least one descriptor of a physical property between consecutive images of the series; 
 calculating secondary visual shifts as differences between said primary visual shifts; 
 calculating tertiary visual shifts as differences between said secondary visual shifts; and 
 determining a signature of the film as a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts. 
 
     
     
       2. The method according to  claim 1 , wherein the series of images includes a particular number P of groups of images at a predetermined rate of coverage of the film, each group of images including a predetermined number N of images. 
     
     
       3. The method according to  claim 2 , wherein:
 for each group of N images, N primary visual shifts are evaluated, N−1 secondary visual shifts are calculated from said N primary visual shifts, and N−2 tertiary visual shifts are calculated from the N−1 secondary visual shifts; and 
 a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts are determined from the N primary visual shifts, N−1 secondary visual shifts and N−2 tertiary visual shifts obtained for the P groups of images. 
 
     
     
       4. The method according to  claim 2 , wherein the groups of images are spaced by a first time shift and the images in each of the groups of images are spaced by a second time shift. 
     
     
       5. The method according to  claim 4 , wherein the first time shift is calculated for each film as a function of various parameters including a duration of the film and a required rate of coverage and the second time shift is predefined and applied independently of the film. 
     
     
       6. The method according to  claim 1 , wherein said at least one descriptor includes a luminance, a movement, a geometrical shape or a color descriptor. 
     
     
       7. The method according to  claim 6 , wherein said at least one descriptor is one of the following descriptors:
 a luminance descriptor for calculating a primary visual shift between two consecutive images in a group of images from a ratio between a number of dark pixels and a number of light pixels in each image of the group; 
 a movement descriptor for calculating a primary visual shift corresponding to an overlapping of contours or dominant shapes between two successive images in the group of images; and 
 an ambiance descriptor for calculating a primary visual shift corresponding to a variation of color between two consecutive images in the group of images. 
 
     
     
       8. An image processing device for determining at least one signature of a film, comprising:
 selection means, for selecting chronologically a series of images from said film; 
 obtaining means for obtaining primary visual shifts as shifts of at least one descriptor of a physical property between consecutive images of the series; 
 calculation means for calculating secondary visual shifts as differences between said primary visual shifts; 
 calculation means for calculating tertiary visual shifts as differences between said secondary visual shifts; and 
 determination means for determining a signature of the film as a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts. 
 
     
     
       9. A computer program including program code instructions for executing the image processing method according to  claim 1  when said program is loaded into and executed in a computer or a data processing system. 
     
     
       10. A non-transitory computer-readable information medium storing a computer program including instructions for executing the steps of the image processing method according to  claim 1 . 
     
     
       11. An image processing device for determining at least one signature of a film, the device being configured to:
 select chronologically a series of images from said film; 
 obtain primary visual shifts as shifts of at least one descriptor of a physical property between consecutive images; 
 calculate secondary visual shifts as differences between said primary visual shifts; 
 calculate tertiary visual shifts as differences between said secondary visual shifts; and 
 determine a signature of the film as a mean value and a standard deviation of the primary, secondary, and tertiary visual shifts.